Arachnids
57 questions tagged Arachnids — spanning every one of the seven Ws.
Why do spiders spin silk that is stronger than steel by weight?
Spider silk is a protein fiber with an exceptional balance of strength and flexibility. It is evolved for web building, prey capture and safety lines.
Why do spiders have venom even if they are not snakes?
Most spiders use venom to immobilize prey and begin digesting it outside the body. Their venom also helps in defense.
Why do scorpions glow under ultraviolet light?
Scorpion exoskeletons contain compounds that fluoresce under UV light. This glow is caused by molecules in the cuticle, not by the scorpion producing light itself.
Why do tarantulas have such hairy bodies?
The hairs help tarantulas sense vibrations, defend themselves and sometimes dislodge irritants. Some species also use special urticating hairs for defense.
Why do ticks swell so much after feeding?
Ticks expand because they take in a very large blood meal relative to their size. Their stretchy cuticle and digestive system allow the body to balloon.
Why do spiders sometimes eat their own web?
Many spiders recycle silk because it is rich in protein and energy. Eating the web lets them reuse material before spinning a new one.
Why do scorpions often hide under rocks and bark during the day?
Scorpions are mostly nocturnal and avoid heat and drying sunlight by sheltering in cool, protected places. Hiding also helps them ambush prey.
Why do camel spiders look so large and fearsome in deserts?
Camel spiders are not true spiders but solifuges, and their big jaws and fast movements make them look alarming. Their size is often exaggerated by perspective and fear.
Why do ticks swell up so much after feeding?
Ticks can expand dramatically because their bodies are built to store a huge blood meal. Their flexible cuticle lets them increase in size many times over.
Why do spiders produce silk in so many different forms?
Spider silk is a family of specialized materials used for webs, egg sacs, draglines, and prey capture. Different glands produce silks with different properties.
Why do orb-weaver spiders rebuild their webs so often?
Orb webs get damaged, lose stickiness, and may not be worth repairing. Rebuilding can be faster and more effective than constant patching.
Why do tarantulas have urticating hairs?
Many New World tarantulas use irritating hairs as a defense against predators. The hairs can be kicked off and cause discomfort or irritation.
Why do spiders sometimes eat their own webs?
Spiders recycle silk protein by consuming old webs. This helps them recover valuable nutrients and build a fresh trap.
Why do male peacock spiders wave their bright abdomens during courtship?
Male peacock spiders use vivid colors and dance-like displays to attract females. The display helps females assess species identity and mate quality.
Why do some spiders use venom instead of wrapping prey in silk right away?
Venom quickly immobilizes prey, making capture safer and easier. Silk can then be used afterward for wrapping or securing the meal.
Why do orb-weaving spiders make webs with sticky spirals but non-sticky spokes?
The sticky spiral traps prey, while the radial spokes provide structure and transmit vibrations. Together they make an efficient hunting trap.
What is a tick and why is it not an insect?
A tick is an arachnid, not an insect, because it has eight legs as an adult and belongs to the same broader group as spiders and mites. Ticks feed on the blood of animals and humans.
What is a spider silk web?
A spider silk web is a structure made from silk that spiders use to catch prey, move around, or protect eggs. Different spider species make different kinds of webs.
What is an arachnid?
An arachnid is an arthropod with eight legs as an adult and no antennae. Spiders, scorpions, ticks, and mites are arachnids.
What is a scorpion sting?
A scorpion sting is the delivery of venom through the scorpion’s tail stinger. Most species are not dangerous to humans, but some can cause serious symptoms.
What is a mite?
A mite is a tiny arachnid related to spiders and ticks. Mites live in soil, plants, water, and on animals, and many are microscopic.
What is a tarantula?
A tarantula is a large, hairy spider belonging to the family Theraphosidae. Despite their size and reputation, most tarantulas are not dangerous to humans.
What is the difference between a spider and an insect?
Spiders are arachnids, not insects. Spiders have eight legs and no antennae, while insects have six legs and usually one pair of antennae.
What is the venom gland in a spider?
A spider venom gland produces venom used mainly to immobilize prey and for defense. The venom is delivered through fangs called chelicerae.
What is a harvestman?
A harvestman is an arachnid often mistaken for a spider, but it is in a different order. Harvestmen usually have a small fused body and extremely long legs.
What is an arachnid exoskeleton?
An arachnid exoskeleton is the hard outer covering that supports and protects spiders, scorpions, ticks, and mites. Like insect exoskeletons, it must be shed as the animal grows.
Where do horseshoe crabs spawn on sandy beaches?
Horseshoe crabs spawn on coastal beaches along the Atlantic coasts of North America and parts of Asia. Their eggs are laid in the sand during spring and early summer high tides.
Where do tailless whip scorpions live in tropical forests?
Tailless whip scorpions live in warm tropical and subtropical regions around the world. Many species hide under bark, rocks, and leaf litter in forest habitats.
Where do camel spiders live in deserts and semi-deserts?
Camel spiders live in arid regions across the Middle East, North Africa, and parts of Asia and the Americas. They shelter in burrows and other shaded ground-level refuges.
Where do whip spiders often live in caves and humid forests?
Whip spiders live in warm, humid regions, especially tropical forests and caves. They are found in the Americas, Africa, Asia, and some Pacific islands.
Where do trapdoor spiders wait in silk-lined burrows?
Trapdoor spiders live in burrows in warm regions around the world, including Australia, the Americas, Africa, and parts of Asia. They hide behind a camouflaged trapdoor at the entrance.
Where do tarantulas live in the wild?
Tarantulas live in warm regions across the Americas, Africa, Asia, and Australia. Many species occupy burrows, forest floor shelters, or tree hollows.
Where do jumping spiders hunt in daylight?
Jumping spiders live in nearly every region of the world except the most extreme polar environments. They are especially common in gardens, forests, grasslands, and buildings.
Where do scorpions live in the wild?
Scorpions live on every continent except Antarctica. They are especially common in deserts, scrublands, and dry forests.
Where do the world’s largest spiders by leg span live?
The largest spiders by leg span, such as giant huntsman spiders, live in caves and forests in Southeast Asia. Records have been linked especially to Laos.
Which spider has the fastest recorded strike to catch prey?
The gladiator spider is known for one of the fastest prey strikes among spiders, using an elastic web-like sling to snatch insects in milliseconds.
Which spider spins the largest orb web?
The Darwin’s bark spider is known for building the largest orb webs, with some spanning more than 25 meters across rivers and lakes.
Which spider has the strongest silk relative to thickness?
The Darwin’s bark spider is famous for producing silk with exceptional toughness, among the strongest known biological fibers for its thickness.
Which arachnid has the longest known legs relative to its body?
The cellar spider has extremely long, thin legs relative to its body, giving it one of the most exaggerated leg-to-body proportions among arachnids.
Which spider is considered the fastest runner among arachnids?
Some huntsman spiders are among the fastest arachnid runners, capable of moving very quickly across surfaces to chase prey or escape danger.
Which arachnid has the most powerful venom for humans?
The Sydney funnel-web spider is one of the most medically dangerous spiders to humans, with venom that can cause severe and potentially fatal symptoms.
Which spider can travel the farthest by ballooning through the air?
Tiny spiders can disperse astonishing distances by ballooning, and some have been found high in the atmosphere and even at sea far from land.
Which arachnid has the longest lifespan recorded in captivity?
Female tarantulas are famous for longevity, with some individuals living 20 to 30 years or more in captivity.
Which spider is known for the largest egg sac relative to its body size?
Some orb-weaving spiders produce very large egg sacs compared with their bodies, but the exact record can vary by species and measurement method.
Which arachnid has the most venom types known in a single species?
Some spiders have very complex venoms containing many different compounds, and arachnid venom diversity is especially high in hunting and defense specialists.
Which spider has the largest known body mass among living arachnids?
The Goliath birdeater is generally recognized as the heaviest spider, reaching masses of over 150 grams in exceptional individuals.
Which arachnid is the most common house-dwelling species worldwide?
The common house spider is among the most widespread indoor arachnids, found in homes across many regions of the world.
How do scorpions glow under ultraviolet light?
Scorpions fluoresce because chemicals in their outer shell absorb ultraviolet light and re-emit it as visible light. This glow is especially visible under a UV lamp.
How do tarantulas sense vibrations without ears?
Tarantulas detect ground vibrations and air movement through sensitive hairs and receptors on their legs. These sensors help them find prey and avoid threats.
How do scabies mites spread from person to person?
Scabies mites spread mainly through close, prolonged skin contact. The mites burrow into the outer layer of skin and lay eggs there.
How do spiders breathe if they do not have lungs like ours?
Many spiders breathe through book lungs, tracheae, or both, depending on the species. These structures move oxygen into the body without true mammalian lungs.
How do ticks find a host to latch onto?
Ticks wait on vegetation and sense nearby hosts through heat, carbon dioxide, vibrations, and odors. When a host brushes past, they grab on and crawl to a feeding site.
How do scorpions survive in deserts with very little water?
Scorpions conserve water with a waterproof exoskeleton and a slow metabolism. They also spend much of their time hidden from the heat.
How do jumping spiders see so well compared with other spiders?
Jumping spiders have unusually sharp vision for spiders, with large forward-facing eyes that help them judge distance. They use that vision to stalk and leap accurately onto prey.
How do spiders detect when prey is caught in a web?
Spiders sense web vibrations through their legs and specialized hairs. The pattern of vibration tells them where the prey is and how big it might be.
How do velvet mites move so dramatically despite being so tiny?
Velvet mites use tiny legs and a soft, velvety body to move through soil, leaf litter, and plant surfaces. Their bright red color and slow, deliberate movement make them easy to notice.
How do spiders use silk for purposes other than webs?
Spiders use silk to wrap prey, protect eggs, make shelters, and help young spiders disperse. Web-building is only one of many silk functions.